Drying and incinerating furnaces

ABSTRACT

A drying and incinerating furnace containing means for effecting desiccation and incineration, in a single process, of a muddy material such as an activated sludge wherein said method is treated from the inlet side or the peripheral portion on the hearth to the outlet side or the central part of the hearth. Airblowing nozzles and raking paddles are provided on rotary pipes for vortically blowing and transporting the material in the furnace.

United States Patent -191 Yamato et al.

[ 51 July 23,1974

1 1 DRYING AND INCINERATING FURNACES [75] Inventors: Yukio Yamato; Koki TeradmBungo Nakamura, all of Tokyo, Japan [73] Assignee: Yamato Sanko Mfg. Co., Ltd.,

Tokyo, Japan [22] Filed: May 10, 1973 [211 App]. No.: 359,000

[30] Foreign Application Priority Data May 10, 1972 Japan 47-46114 [52] U5. Cl 110/13, 110/36, 110/171 [51] Int. Cl. F23g 5/00 [58] Field of Search 110/7 R, 8 R, 13, 36, 171

[56] References Cited UNITED STATES PATENTS 2,568,657 9/1951 Pfau 110/36 3,319,587 5/1967 Albertson et a1. 110/8 3,605,656 9/1971 Stribling 110/13 3,671,167 6/1972 Nakana .1 110/7 3,741,136 6/1973 Stookey ll0/l7l Primary Examinerl(enneth W. Sprague Attorney, Agent, or FirrnStewart and Kolasch, Ltd.

57 ABSTRACT A drying and incinerating furnace containing means for effecting desiccation and incineration, in a single process, of a muddy material such as an activated sludge wherein said method is treated from the inlet side or the peripheral portion on the hearth to the outlet side or the central'part of the hearth. Air-blowing nozzles and raking paddles are provided on rotary pipes for vortically blowing and transporting the material in the furnace.

11 Claims, 3 Drawing Figures PATENTEDJIIWIQH F i g SHEEI 1 BF 2 I PATENTEU sum 2 or 2 Fig 3 1 i DRYING AND INCINERATING FURNACES BACKGROUND AND SUMMARY OF THE INVENTION The present invention relates to a drying and incinerating apparatus which can be used for the treatment of waste products. More particularly, the present invention is directed to a novel and improved apparatus having treating means for drying and incinerating, in a single process, muddy materials, for example an activated sludge, which, in the past, were not treatable using conventional furnaces.

I-Ieretofore, it has been disadvantageous for conventional furnaces to treat a muddy material, such as activated sludges, because when treated in said conventional furnace, they form into clinkers which not only prevent their incineration but also consume a large amount of heat energy, resulting in the rapid deterioration, due to the heat, of the furnace wall as well as other components disposed in the furnace for supply, agitation, and/or transportation of the materials.

A double-process treatment has been tried, in which the muddy material is first treated in a dryer and then retreated in an incinerator, said treatment, requiring a dryer, an incinerator, and conveying means therebetween. This is undesirable because the cost of the equipment is very high and the material handling is complicated.

Accordingly, it is an object of the present invention to provide an improved apparatus free of the abovementioned disadvantages.

Another object of the present invention is to provide an improved apparatus, in which a muddy material, especially an activated sludge, can be dried and incinerated in a single process.

A further object of the invention is to provide an improved apparatus, in which the overall operation is substantially simplified.

Still another object of the present invention is to provide an improved apparatus which neither discharges incompletely treated materials nor exhausts injurious gases to the atmosphere.

. A still further object of the present invention is to provide an improved apparatus which possesses a high heatefficiency.

An even further object of the present invention is to provide an improved apparatus which is endurable over a long period of time.

An even still further object of the present invention is to provide an improved apparatus that contains a treating means for effecting desicration, incineration, and vortical transportation of the material being handled from the inlet to the outlet of the apparatus.

Other objects and further scope of applicability of the present invention will become apparent from the detailed description given hereinafter; it should be understood, however, that the detailed description and specific examples, while indicating preferred embodiments of the invention, is given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.

Pursuant to the present invention, the furnace comprises a housing, having a vertical hollow-cylindrical wall and a circular hearth, the centers of said wall and hearth being aligned with each other. An inlet port is provided in the wall for introducing the material to be treated on the peripheral portion of the hearth and the outlet port is located in the center of the hearth for removing the treated material from the housing. A device for treating the material is mounted in the housing and comprises a rotary tube vertically inserted through the outlet port from the underside of the hearth into the housing. An air supply system communicates with the bottom of the rotary tube, and a drive system is associated with the rotary tube for rotating said tube. The rotary tube is rotatably supported by the housing. A plurality of nozzles and blades are provided on the underside of each branch pipe. A burner is provided in the wall and a gas exhauster is mounted on the top of the housing. A plurality of radial branch pipes are secured to and communicated with the top of the rotary tube and are rotatable therewith.

In a preferred embodiment of the present invention, the nozzle is disposed with a predetermined angle about the axis of the branch pipe from the vertical plane toward the rotary direction of the branch pipe, so as to blow the material in the direction of rotation of the branch pipe. The blade is secured to the branch pipe in a manner that its flat face is inclined with a preselected angle to thedirection of rotation of the branch pipe with respect to the vertical plane passing through the axis of the branch pipe. As the rotary tubes rotate, the blades rake and transport the material centripetally and vortically to the center of the hearth or the outlet port.

BRIEF DESCRIPTION OF THE DRAWINGS The present invention will become more fully understood from the detailed description given hereinbelow and the accompanying drawings, which are given by way. of illustration only and thus are not limitative of the present invention and wherein,

FIG. 1 is an elevation, partially in section, of an embodiment of the furnace of the present invention;

FIG. 2 is a section taken along the line II-II of FIG. 1', and

FIG. 3 is a cross-sectional view illustrating, on a relatively enlarged scale, the radial branch pipe provided with nozzles and blades.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIGS. 13, the furnace illustrated therein comprises a housing 1 having a vertical, hollow, cylindrical wall la and a circular hearth 1b, the centers of said cylindrical wall and circular hearth being aligned with each other. The housing 1 has an outlet port 2 provided in the center of hearth 1b for discharging the treated material from the housing. A rotary tube 3 has its lower portion rotatably supported by housing 1 and its upper portion vertically inserted from the underside of hearth lb into the inside of the housing through and concentrically with outlet port 2. A plurality of branch pipes 4 have their bases fixed to and internally communicated with the top of rotary tube 3, each branch pipe extending radially from the rotary tube. The rotary tube 3 is operatively connected with a geared motor 20 through a bevel gear transmission 10, whereby the rotary tube as well as the branch pipes are rotated in the direction shown by the arrows of FIG. 2. The rotary tube 3 has its bottom end internally commu- 3 nicated with a blast tube 11 connected to the delivery side of a fan 12. A plurality of nozzles 5 and blades 6 are provided on the'underside of each branch pipe 4. The nozzles 5 are preferably disposed with their axis inclined with respect to the vertical plane containing the axis of the branch pipe, as seen in FIG. 3, in order to blow thematerial in the direction of rotation of the branch pipe. As shown in FIGS. 2 and 3, blade 6 is secured to the branch pipe 4 with its flat face inclined relative to the vertical plane containing the axis of the branch pipe, so that, while the branch pipe rotates, the blades rake the material on the hearth in a centripetally vortical way, thereby gathering the material in the central portion of. the hearth. An inlet device 7 including a material supply tube 22 and a screw conveyor 23 mounted therein is disposed in the cylindrical wall la in a manner such that the material to be treated is deposited on the peripheral portion of the hearth 1b. An exhaust means 9 is mounted on the top of housing 1 for the exhaust of gas from the housing. A gas or oil burner 8 is provided in the Wall 1a. In order to quickly heat up the temperature in the housing and exhaust the dustfree gas after separation of the dust therefrom, the axis of the burner is preferably arranged to direct its products tangentially to an imaginary circle spaced a predetermined distance from the center of the cylindrical wall and said burner is also disposed in a position slanted to the surface of the hearth. A water bath 13 is disposed beneath outlet port 2 for chilling the treated material or ash that drops through the outlet. A water pipe l4 is connected with the bath for supplying the waterthereto and the ash is removed through a drain pipe 15 together withthe water.

In another embodiment of the present invention, not shown, the water system for treating the ash can be substituted by a chute system, in which a chute is placed beneath the outlet port to guide the ash into a take-up device. I

The manner of operation of the inventive furnace describedin connection with the drawings will now be explained. 1

. First, the burner 8 is fired to flame and heat the inside of the housing lupto a desired temperature for treatment. Then, the fan 12 is started to cause air to blow out through .nozzles 5 against the surface of hearth lb, while the rotary tube 3 is rotated. Meanwhile, the material to bev treated is deposited on hearth 1b through material supply tube 22 by screw conveyor 23. The material located on the peripheral part of the hearth is gradually and centripetally and vortically moved toward the central part or the outlet port by blades 6, while it is heated and dried by the air-blowing through nozzles 5. The blades 6 penetrate deeply into the material deposit which serves for quickly drying and insuring complete combustion of the material.

Until the material is dried to a critical moisture content, it still possesses a wet bulb temperature. But, after exceeding the critical moisture content, the material soon reaches its firing temperature and makes a violent complete combustion through the help of fresh airsupply through nozzles 5. Thus, when the material arrives in the central part of the hearth, it is completely converted into ash and drops through outlet port 2 into the bath therebeneath, where the ash is chilled and then removed from the apparatus through drain pipe 15. Some ash is rolled up by the rotational air-flowing in the housing. However, it is separated from the exhausting gas by centrifugal motion and returned into the material on the hearth along the wall.

It is advantageously simple to operate the furnace of the present invention, because the material to be treated can be easily transported from the inlet or the peripheral portion of the hearth to the outlet port by the rotation of the rotary tube 3, as described above.

Another advantageous effect of the furnace of the present invention is that it is very high in heatefficiency since the material is burned after being dried to the proper moisture content. The nozzles and blades provided on the branch pipes can supply air and heatenergy deep into the material all over the surface of the hearth, so that a complete combustion following the rapid drying of the material is achieved. This results in neither discharging incompletely burned products nor exhausting injurious gases. The housing as well as other components, for example, the rotary tube, the branch pipes, and the blades disposed in the high temperature environment are endurable for many years service, because the fan causes fresh air to pass through and about these elements thereby protecting them from heatdamage.

The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications are intended to be included within the scope of the following claims.

It is claimed:

1. An apparatus for drying and incinerating materials which comprises a chamber containing the material to be treated, inlet means for supplying the material to be treated to the chamber, outlet means forremoving the treated material from the chamber, said outlet means including an outlet port centrally disposed in the bottom of said chamber, treating means provided in said chamber for blowing the material deposited on the bottom of said chamber and transporting it vortically toward said outlet port, said treating means comprising a rotary tube mounted for rotation and extending vertically through the outlet port, said rotary tube being provided with a plurality of radially extending branch pipes, said branch pipes containing a plurality of nozzles and blades provided on the underside thereof, airsupply means communicating with said rotary tube and drive means communicating with said rotary tube for rotating the same, burner means communicating with the chamber and gas exhaust means associated with said chamber for removing the gases of combustion therefrom.

2. The apparatus of claim 1, wherein said chamber has vertical, cylindrical walls and a circular hearth forming the bottom of said chamber, the centers of said cylindrical walls and said circular hearth being aligned with each other and said outlet port being concentrically disposed in said hearth.

3. The apparatus of claim 1, wherein said airsupply is concentrically disposed within said outlet port, the

branch pipes internally communicating with the top of the rotary tube inside the chamber, and the bottom of said rotary tube internally communicating with the airsupply means.

6. The apparatus of claim 1, wherein each nozzle has an axis directed toward the surface of said chamber bottom with a predetermined angle inclined toward the rotating direction of said branch pipe.

7. The apparatus of claim 1, wherein each blade extends nearly to the surface of said chamber bottom, said blade having a face inclined toward the rotating direction of said branch pipe with respect to the axis of said branch pipe for centripetally and vortical transporting the material.

8. The apparatus of claim 1, wherein said inlet means comprises a material-supply tube disposed in said cylindrical wall and screw conveyor means provided therein for depositing the material on the peripheral portion of said chamber bottom.

9. The apparatus of claim 1, wherein said outlet means comprises a water system including a bath for receiving the treated material dropped through said outlet port, a water supply pipe connected to said bath, and a discharge pipe for discharging the treated material mixed with water.

10. The apparatus of claim 1, wherein said outlet means comprises a chute system disposed under said outlet port for guiding the treated material to a predetermined location outside the chamber.

11. The apparatus of claim 1, wherein said burner means is disposed in the chamber wall with its axis being directed tangentially to an imaginary circle spaced at a predetermined distance from the center of said cylindrical wall and slanted to the surface of said chamber bottom. 

1. An apparatus for drying and incinerating materials which comprises a chamber containing the material to be treated, inlet means for supplying the material to be treated to the chamber, outlet means for removing the treated material from the chamber, said outlet means including an outlet port centrally disposed in the bottom of said chamber, treating means provided in said chamber for blowing the material deposited on the bottom of said chamber and transporting it vortically toward said outlet port, said treating means comprising a rotary tube mounted for rotation and extending vertically through the outlet port, said rotary tube being provided with a plurality of radially extending branch pipes, said branch pipes containing a plurality of nozzles and blades provided on the underside thereof, air-supply means communicating with said rotary tube and drive means communicating with said rotary tube for rotating the same, burner means communicating with the chamber and gas exhaust means associated with said chamber for removing the gases of combustion therefrom.
 2. The apparatus of claim 1, wherein said chamber has vertical, cylindrical walls and a circular hearth forming the bottom of said chamber, the centers of said cylindrical walls and said circular hearth being aligned with each other and said outlet port being concentrically disposed in said hearth.
 3. The apparatus of claim 1, wherein said air-supply means includes fan means.
 4. The apparatus of claim 1, wherein said drive means includes a geared motor means which is adapted to engage gear transmission means associated with the bottom portion of the rotary tube.
 5. The apparauts of claim 1, wherein the rotary tube is concentrically disposed within said outlet port, the branch pipes internally communicating with the top of the rotary tube inside the chamber, and the bottom of said rotary tube internally communicating with the air-supply means.
 6. The apparatus of claim 1, wherein each nozzle has an axis directed toward the surface of said chamber bottom with a predetermined angle inclined toward the rotating direction of said branch pipe.
 7. The apparatus of claim 1, wherein each blade extends nearly to the surface of said chamber bottom, said blade having a face inclined toward the rotating direction of said branch pipe with respect to the axis of said branch pipe for centripetally and vortical transporting the material.
 8. The apparatus of claim 1, wherein said inlet means comprises a material-supply tube disposed in said cylindrical wall and screw conveyor means provided therein for depositing the material on the peripheral portion of said chamber bottom.
 9. The apparatus of claim 1, wherein said outlet means comprises a water system including a bath for receiving the treated material dropped through said outlet port, a water supply pipe connected to said bath, and a discharge pipe for discharging the treated material mixed with water.
 10. The apparatus of claim 1, wherein said outlet means comprises a chute system disposed under said outlet port for guiding the treated material to a predetermined location outside the chamber.
 11. The apparatus of claim 1, wherein said burner means is disposed in the chamber wall with its axis being directed tangentially to an imaginary circle spaced at a predetermined distance from the center of said cylindrical wall and slanted to the surface of said chamber bottom. 